It is known that the vase life of cut flowers can be extended by use of nutrients and/or water uptake stimulants in combination with certain chemical preservatives. Examples of such nutrients include carbohydrates such as sucrose, fructose, glucose, lactose and maltose. Examples of water uptake stimulants include acidulants, such as citric acid, glycolic acid, malic acid and aluminium sulphate, and anionic and non-ionic surfactants. Chemical preservatives currently in use include biocides, such as isothiazolinones, bronopol and quaternary ammonium salts. Several flower conditioning compositions which contain various mixtures are commercially available, e.g., Chrysal®. These compositions are effective in extending the vase life of cut flowers up to several days. Doi and Reid, Hort. Science 30: 1058-1060 (1995), describe a vase solution containing Physan (a benzalkonium disinfectant) and sucrose, which prolonged the florets life but also promoted bud opening.
Biocides have been employed to inhibit growth of micro-organisms such as bacteria and algae. Microbial growth has an unfavourable effect on the effectiveness of cut flower nutrients and water uptake stimulants that have been dissolved in vase water, thus adversely affecting the longevity of the flowers, while in addition turning the water murky and causing it to smell foul.